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White fused alumina—almost as hard as a diamond


White fused alumina is a synthetic product that is created by melting high-grade aluminium oxide in an electric arcing process—accordingly the proportion of aluminium oxide is over 99%. Besides the transparency, an excellent property of white fused alumina is the extraordinarily high degree of hardness—only diamonds are harder. This high degree of hardness is a challenge for any milling process. Our SEPASIL® micronized white fused alumina powders are characterized by a customized steep grading curve. The last refining operation is a surface modification that is matched specifically to the respective application.


  • depending on the processing: a rounded or fragmented particle shape
  • high degree of hardness of 9 (Mohs)
  • density of 3.95 g/cm3
  • chemically inert
  • high chemical resistance
  • very close particle size distribution
  • transparent behaviour in many binding agent systems

Main applications

  • Highly abrasion-resistant wood coatings and decorative coatings
  • Laminates
  • Cast resin insulators and high-voltage insulators

In short: a top product that provides reliable service as a high-performance filler. You can also benefit from this!